Means for suppressing oscillator-generated noise in doppler proximity fuzes

Abstract

1. In a doppler proximity fuzing system including an oscillating detector oviding diode detection, an antenna to which the output of said oscillating detector is coupled, and an amplifier to which the detected signal from said oscillating detector is fed, the improvement comprising means for suppressing oscillator-generated noise, said means including a 45° r-f phase shift network connected between the output of said oscillating detector and said antenna, diode detection means connected to said antenna and poled oppositely to the diode detection provided by said oscillating detector, the detected signal from said diode detection means being fed to said amplifier along with the detected signal from said oscillating detector, and means to which at least one of said detected signals is fed prior to application to said amplifier for adjusting the magnitude of the detected oscillator-generated noise appearing in one of said detected signals to be substantially equal to the magnitude of the detected oscillator-generated noise appearing in the other of said signals.

We claim as our invention: 
     
       1. In a doppler proximity fuzing system including an oscillating detector providing diode detection, an antenna to which the output of said oscillating detector is coupled, and an amplifier to which the detected signal from said oscillating detector is fed, the improvement comprising means for suppressing oscillator-generated noise, said means including a 45° r-f phase shift network connected between the output of said oscillating detector and said antenna, diode detection means connected to said antenna and poled oppositely to the diode detection provided by said oscillating detector, the detected signal from said diode detection means being fed to said amplifier along with the detected signal from said oscillating detector, and means to which at least one of said detected signals is fed prior to application to said amplifier for adjusting the magnitude of the detected oscillator-generated noise appearing in one of said detected signals to be substantially equal to the magnitude of the detected oscillator-generated noise appearing in the other of said signals. 
     
     
       2. A doppler proximity fuzing system in which oscillator-generated noise is suppressed, said system comprising in combination: an oscillating detector, an antenna to which the output of said oscillating detector is coupled, said oscillating detector providing a first detected signal consisting of a first doppler frequency signal obtained from the mixing of the oscillation signal with the reflected signal from a target and a first noise signal obtained from the detection of noise amplitude modulation on the oscillation signal, means cooperating with said antenna and said oscillating detector for obtaining a second detected signal consisting of a second doppler frequency signal in quadrature with said first doppler frequency signal and a second noise signal 180° out of phase with said first noise signal, an amplifier to which said first and second detected signals are fed, means to which at least one of said detected signals is fed prior to application to said amplifier for adjusting the magnitude of said first noise signal to be substantially equal to the magnitude of said second noise signal, a detonator, and means connected to the output of said amplifier for activating said detonator when the amplified signal from said amplifier reaches a predetermined value. 
     
     
       3. A doppler proximity fuzing system in which oscillator-generated noise is suppressed, said system comprising in combination: an oscillating detector, an antenna to which the r-f output of said oscillating detector is coupled, a 45° r-f phase shift network connected between said antenna and said oscillating detector, a diode having its cathode connected to said antenna, a first resistor which is adjustable having one end connected to the plate of said diode, an amplifier, the other end of said first resistor being connected to the input of said amplifier, a second resistor having one end connected to the detected output of said oscillating detector and the other end also connected to the input of said amplifier, said first and second resistors being chosen so that the detected oscillator-generated noise fed to said amplifier from said oscillating detector has a magnitude substantially equal to the detected oscillator-generated noise fed to said amplifier from said diode, a detonator, and a firing circuit connected between said amplifier and said detonator for firing said detonator when the output of said amplifier reaches a predetermined amplitude. 
     
     
       4. In a doppler proximity fuzing system in which oscillator generated noise is suppressed, an oscillating detector providing an r-f oscillation signal at a first output and a first detected signal at a second output, an antenna, a 45° r-f phase shift network connected between said oscillating detector first output and said antenna, a diode having its cathode connected to said antenna for providing a second detected signal, each of said detected signals consisting of a doppler frequency signal obtained by mixing said r-f oscillation signal with the reflected signal from a target received by said antenna and a noise signal obtained from the detection of noise amplitude modulation on said r-f oscillation signal, said doppler frequency signals being in phase quadrature and said noise signals being 180° out of phase, an amplifier having an input and an output, a resistor connected between said oscillating detector second output and said amplifier input, an adjustable resistor connected between the anode of said diode and said amplifier input for balancing the magnitudes of said noise signals whereby oscillator generated noise is suppressed, a detonator, and a firing circuit connected between said amplifier output and said detonator for firing said detonator when the output of said amplifier reaches a predetermined amplitude.